Stadiums are one of the few times a large number of people gather to a controlled place, so while most of them are focused on the field, we can use this rare mass gathering to do some cool studies.
With so much human in one confined space, there would have to be some kind of effect on the planet, right?
Well, in fact, fans in stadiums have been found to affect seismometer readings, registering what resemble tiny earthquakes. They can also affect the humidity of the air inside a stadium! And the loudest a stadium crowd has ever been rivals the sound of a jet.
PNSN: One year ago, Seattle Seahawks 12th Man Earthquake
AL.com: Tide fans turn up heat, humidity on game days
Guinness World Records: Kansas City Chiefs fans reclaim record for loudest crowd roar at sports stadium